1. Field of the Invention
The present invention relates to an external filter device particularly for tanks and aquariums.
2. Description of the Prior Art
Conventional external filters include a container that is internally provided with an intake chamber and with a discharge chamber that are separated by a filtration part and are connected to the outside by means of respective openings or ducts.
In a known device, the container is open at the top and one of its upper edges is partially depressed and folded outward so as to form a part for anchoring to the upper rim of the tank or aquarium, and also forming a discharge opening.
The device has a pump for circulating the water of the aquarium through the container. The pump is generally a centrifugal pump which is partially immersed in the container and is driven by an electric motor which is located outside the container.
The bladed impeller of the pump is accommodated in the intake chamber of the container, and its axis passes through the wall of the container with the interposition of suitable gaskets.
The intake chamber is connected to the aquarium by a suction duct which is provided with appropriate elbows and connectors; its free end is partially immersed in the water.
A drawback of conventional external filters is the leakage of water due to a poor seal between the connectors and the gaskets fitted on the impeller axis.
Another drawback is the need to partially fill the container to allow priming in the pump and the difficulty of this operation due to air bubbles that form in the suction duct. Another drawback is the relative complexity and difficulty of the operations for installing the device, and particularly for assembling the various suction connectors and tubes and for their vertical adjustment. These operations require a certain dexterity and do not always yield satisfactory results.
Another drawback of prior art filters is their large number of component parts and their complex assembly with consequent high manufacturing cost.
The aim of the present invention is to eliminate the drawbacks described above by providing an effective external filter device for aquariums which has a particularly simple structure and has no sealing problems.
An object of the invention is to provide a filter device which substantially has no pipes and connectors to be assembled, so as to avoid complicated and onerous operations for watertight installation.
Another object of the invention is to provide a filter device having low manufacturing and maintenance costs.